SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1131d456e81ef6dad3c1f60324df9a40839648acb2796f6f513df734782f3a3' 
  AND token = 'zDcqTn99MBbb3VPWJs2pGpgQwhjDBsiZSU57l8deqoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}